The invention relates to a wheel suspension for a front axle of a motor vehicle with a steering gear, in particular intended for an all-terrain vehicle, with a pulled up drag link, and the latter has double transverse links positioned on it, respectively, comprised of a steering triangle that is positioned with the ability to swing, and one of the transverse links is arranged above a wheel and the other transverse link is arranged with a steering tie rod as well as a stabilizer underneath a rotation axis of the wheel, and a geometric swiveling axis as well as an elastokinematic swiveling axis are generated.
In German Patent Document DE 40 12 418 A1, a wheel suspension is disclosed that is constructed as a double transverse link with a transverse link on the one side of a pulled up drag bearing, that is positioned, with the ability to swing, in a holder which is mounted on the side of the assembly, and which also supports the upper end of a MacPherson strut unit/shock absorber leg. The other end of the MacPherson strut unit/shock absorber leg is mounted on the other, lower transverse link that is coupled with the drag bearing. In addition, Matschinsky, W., xe2x80x9cWheel Guides for Road Vehicles,xe2x80x9d Txc3x9cV Rheinland Publishers, 1987, p. 246, FIG. 11.2, discloses a single-wheel suspension for steerable wheels with two transverse links, arranged one above the other, consisting of steering triangles mounted on the drag bearing, respectively, by way of a bearing. The bearings on the assembly side are mounted on axles that are arranged obliquely in relation to the longitudinal center axis of the vehicle.
The subject-matter of the invention comprises providing a wheel suspension for steerable wheels of a front axle of a motor vehicle that realizes a slightly understeered driving performance when going through curves or when going straight ahead, while forces act upon the wheel.
According to the invention, this objective is achieved with the characteristics of a bearing on the side of the drag bearing of the upper transverse link and a bearing of the steering tie rod are arranged on the drag bearingxe2x80x94in relation to the direction of movementxe2x80x94behind a vertical transverse plane of the center of the wheel; and wherein a corresponding other bearing on the side of the drag bearing of the lower transverse link is arrangedxe2x80x94in relation to the direction of movementxe2x80x94in front of the vertical transverse plane of the center of the wheel; and wherein a geometric swiveling axis for steering the wheels or a trailing axis with a piercing point results in the wheel contact plane in close proximity or inside the tread and in front of the vertical transverse plane of the center of the wheel; and wherein a position is created for the elastokinematic swiveling axis by way of the upper bearing on the side of the drag bearing and by way of a pole formed by the radius vectors of the lower transverse link and the steering tie rod whichxe2x80x94in relation to the direction of movementxe2x80x94runs behind the vertical transverse plane of the center of the wheel and outside of the tread through pole. Other advantageous characteristics are reflected in the preferred embodiments.
The primary advantages achieved with the invention are that the driving performance of the vehicle, especially of an all-terrain vehicle, remains slightly understeered when forces, such as braking forces, lateral forces and acceleration forces act upon the wheel. Major changes of the wheel position are to be avoided while these forces are acting upon the wheel because this can unfavorably affect the driving performance in curves as well as when driving straight ahead, and it can cause unstable driving performance.
In principle, these advantages are achieved by, in particular, the position of the elastokinematic swiveling axis of the wheel suspension is determined on the basis of the positioning of the upper and lower transverse links, one above the other, with respect to the vertical transverse plane of the center of the wheel and on the basis of the soft and hard identifications of the transversal swing arm bearings, adjusted in relation to each other, on the side of the assembly in radial and axial load directions.
The advantageous effects of the front wheel suspension are mainly achieved in that a bearing on the side of the drag bearing of the upper transverse link and a bearing of the steering tie rod are arranged on the drag bearingxe2x80x94in relation to the direction of movementxe2x80x94behind a vertical transverse plane of the center of the wheel. Furthermore, a corresponding, additional bearing on the side of the drag bearing of the lower transverse linkxe2x80x94in relation to the direction of movementxe2x80x94is located in front of the vertical transverse plane of the center of the wheel. In particular, the geometric swiveling axis or the trailing axis will turn out to be with its piercing point in the wheel contact surface outside and close to the tread or close to the wheel plane and in front of the vertical transverse plane of the center of the wheel.
Radius vectors run through the bearing on the side of the drag bearing of the lower transverse link and through the bearing on the side of the draft bearing of the steering tie rod, forming a lower pole at their point of intersection for the elastokinematic swiveling axis whichxe2x80x94in relation to the direction of movementxe2x80x94has a piercing point in the wheel contact surface plane behind the vertical transverse plane of the center of the wheel and close to the tread. The bearing on the side of the drag bearing of the upper transverse link forms an upper pole for the elastokinematic swiveling axis and thus helps determine the position of the swiveling axis. The radius vectors run along one of the front wheel guide arms of the lower transverse link and along the steering tie rod, which is why the direction of the radius vectors is predetermined.
Seen from a side view of the wheel, the shock absorber leg is arranged in a transverse plane with the trailing axis. Looking at the wheel from a front view, the center line of the shock absorber leg is arranged at a less steep angle in relation to the wheel contact plane than the trailing axis or the geometric swiveling axis. A shock absorber leg is mounted with its lower end on the lower transverse link, while the upper end is supported, with the ability to swing, in a step bearing. The latter is connected with the vehicle assembly and receives two bearings of the upper transverse link arranged on a swiveling axis.
To achieve the antidive effect and the antisquat effect, the swiveling axis of the two bearings on the side of the assembly of the upper transverse linkxe2x80x94seen from a side view of the wheelxe2x80x94isxe2x80x94in relation to the direction of movementxe2x80x94inclined backward with regard to the wheel contact plane, and the swiveling axis of the two bearings on the side of the assembly of the lower transverse link is realizedxe2x80x94in relation to the direction of movementxe2x80x94as ascending toward the back. In particular, a pitch pole results for an antidive and an antisquat above the wheel rotation axis, parallel to these axes due to vectors running through the bearings on the side of the drag bearing.
Based on the predetermined position of the geometric swiveling axisxe2x80x94around which the wheels are adjusted during a steering motionxe2x80x94and the elastokinematic swiveling axis, a position in relation to the wheel and in relation to the wheel contact surface becomes possible allowing for wheel position changes that facilitate a slightly understeered driving performance. Therefore, among other things, the two front bearings on the side of the assembly of the two transverse linksxe2x80x94in relation to the direction of movementxe2x80x94are arranged closer to the vertical transverse plane of the center of the wheel than the two back bearings on the side of the assembly of the two transverse links, and they are assigned a harmonized radial and axial identification.
The elastokinematic movement of the wheel or of the wheel suspension under load and while driving occurs specifically in the longitudinal direction of the vehicle, especially for brake and acceleration forces. For this purpose, the bearings on the side of the assembly of the upper transverse link and of the lower transverse link have a softer identification in the axial load direction than in the radial load direction. The lower bearings on the side of the assembly of the transverse link have a harder identification vis-à-vis the upper bearings on the side of the assembly of the transverse link in the radial load direction. The bearings of the upper transverse link, on the other hand, have a softer axial identification than the other bearings of the lower transverse link. In particular, seen in the direction of movement, the front bearing of the upper transverse link can also be realized as rigid in the axial and radial directions, and it can form a pivot, with the back bearing having a soft identification in the radial direction.